ATM, you will have to play for 75 minutes in order to buy 1 T round, I'd say at max you could have it be 24 points, that way it takes exactly 2 hours of playing in order to get enough for 1 T round.
If you were to change it to 100-150 points like you said, it will take people about 8-12 hours of playing just to be able to buy 1 T round, in this case most people would just buy perm weapons or cosmetics instead.
The only problem is that people that have played a lot, or have donated a lot, will have a huge amount of points at their disposal.